Did you know there are four types of anodising? Let’s look at each one briefly in turn:
Chromic acid
Chromic acid is a protective and thin coating that is used mainly in aerospace, as it offers a very high degree of corrosion resistance. It’s also a common pre-treatment for parts that are unable to handle harsher sulphuric acid.
Sulphuric acid anodising
Sulphuric acid anodising is used to create a clear and thin coat that prevents corrosion and offers an attractive aesthetic finish. It’s the most heavily used form of anodising, and it’s commonly used for interior parts and products. It can be used across many applications, including decorative and architectural finishes. Find out more at https://www.poeton.co.uk/surface-treatments/anodising/sulphuric-acid-anodising.
Hardcoat anodising
Hardcoat anodising is the third approach, and this provides a thicker, harder coat to boost wear resistance and prevent corrosion on the material surface. It’s typically used for industrial parts that will experience heavy wear, and for parts that need to be lapped, grounded or honed, such as firearms or engine components.
Organic acid anodising
Organic acid anodising is a thicker and harder coating, again, used for parts that will be heavily worn, and where excellent corrosion protection and wear resistance are needed. Again, it’s used for engine parts and it uses phosphoric acids and other organic acids, which can be chosen to apply particular colours.
These are the four main types of anodising, and treatment specialists will choose the most appropriate for the application and end purpose, using a variety of techniques to gain the desired aesthetic and functional finish.